Lyme (IgG and IgM) Antibody Confirmation

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1 Pathology & Laboratory Medicine Lyme (IgG and IgM) Antibody Confirmation TEST UPDATE: New Test Notification Date: 1/9/2013 Effective Date: 1/7/2013 CONTACT INFO Call Or visit MEDICAL DIRECTOR Greg Sharp M.D. Phone: Assay Information: On January 7, 2013, the Chemistry Laboratory began offering Lyme (IgG and IgM) antibody confirmation testing by Western Blot. This testing will use MarDx Marblot Western Blot strips and will be performed on the TrinBlot processor and scanner (Trinity Biotech). Previously this test was sent to Mayo Medical Laboratories which uses Immunoblot (Viramed ViraBlot ) Western blot technology. Lyme antibody confirmation testing will be performed on Tuesday and Friday with results available the same day. Lyme antibody confirmation testing by Western Blot cannot be performed without a Lyme antibody screen and will only be performed when the antibody screen results are positive or equivocal. If you have any questions concerning this change, please contact Dr. Gregory Sharp in the laboratory ( ) or by [email protected] Method: The MarDx B. burgdorferi Strip Test System is a Western blot assay that utilizes antigens of B. burgdorferi (Strain B 31) which are separated in the presence of SDS (sodium dodecyl sulfate) by polyacrylamide gel electrophoresis. The resolved protein bands are transferred by electrophoresis to a nitrocellulose membrane. The membrane is dried, cut into strips and packaged. Serum is incubated with the Marblot strips. If specific antibodies to individual proteins are present, they will bind to the corresponding B. burgdorferi antigen bands. Unbound serum is washed from the strip then the bound B. burgdorferi specific antibody is reacted with alkaline phosphatase conjugated anti-human IgG for the IgG strips and anti-human IgM for the IgM strips. The strip is washed to remove unbound conjugated antibody then reacted with a precipitating color developing solution which deposits a purple precipitate on antibody reacted antigen bands. Bands are visualized, scored for intensity relative to the 41 kda band of the Weakly Reactive control and recorded. Clinical Application: Lyme disease is a multisystem disease caused by a spirochete, Borrelia burgdorferi. The organism is transmitted through an arthropod vector from an animal reservoir. The symptoms of Lyme disease may be nonspecific and confused with other disease processes. Serologic methods are most commonly used for the presumptive diagnosis of infection. The use of the Western Blot is helpful in characterizing the specificity of the antibody response to B. burgdorferi. This discrimination is not possible with initial serologic screen-

2 2 Pathology & Laboratory Medicine Test Update: Lyme antibody Confirmation ing methods because these methods measure the total antibody response only. It is reported that patients with Lyme disease produce antibodies of the IgM class during the first few weeks after onset of Erythema Migrans (red lesion at the site of the tick bite) and produce IgG antibodies more slowly. Both IgM and IgG titers can remain positive for many months or years. IgM western blot is considered positive if any two of the following three significant bands are present: 24 kda, 39 kda and 41 kda. IgG western blot is considered positive if any five of the following ten significant bands are present: 18 kda, 23 kda, 28 kda, 30 kda, 39 kda, 41 kda, 45 kda, 58 kda, 66 kda and 93 kda. Assay Limitations: Western blot testing should not be performed as a screening procedure. The MarDx Marblot Western Blot test system should only be used to test serum samples which have been found positive or equivocal using an EIA, CIA or IFA test procedure. The diagnosis of Lyme Disease must include clinical evaluation and should not be based only on detection of antibodies to B. burgdorferi. A negative western blot does not exclude the possibility of infection with B. burgdorferi. A positive IgM Western Blot is only meaningful during the first 4 weeks of illness. If the patient has been ill for longer than 4-6 weeks and the IgG Western Blot is negative, it is unlikely that the patient has Lyme disease even if the IgM Western Blot is positive. The continued presence or absence of antibodies to B. burgdorferi cannot be used to determine the success or failure of therapy. Samples with marked icterus, hemolysis and/or lipemia will interfere with the ability to perform this testing. Studies have demonstrated that antibiotic therapy may or may not affect the seroconversion from IgM to IgG during the course of the disease. A positive B. burgdorferi IgG and/or IgM Western Blot result only indicates probable immunologic exposure, however, the presence of immunologic response has not been correlated with active infection. Sera from patients with other spirochetal diseases such syphilis, yaws, pinta, leptospirosis, relapsing fever and periodontal disease may give false positive results. Individuals with connective tissue autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosis, and individuals with anti-nuclear antibody may also give false positive results. Individuals with other bacterial and viral infections such as Rocky Mountain Spotted Fever, Epstein -Barr virus and cytomegalovirus may also have antibodies which cross-react with B. burgdorferi. Date: January, 2013

3 3 Pathology & Laboratory Medicine Test Update: Lyme Antibody Confirmation Test Information: Test Name: Lyme Antibody Confirmation, Serum Test Code: LYMWB FAH Translation Code: FAH5531 CPT Code: x 2 Method: Western Blot assay Sample Requirements: Days performed: Collect 3.5 ml serum gel tube and submit 0.3 ml of serum. Stable for 7 days refrigerated. Markedly lipemic, icteric or hemolyzed samples will not be accepted. Tuesday and Friday (run starts at 8 a.m.) Analytical Time: Same day Expected Value: IgG Western Blot: Negative IgM Western Blot: Negative Interpretive Information: Negative IgG / Negative IgM: Specific serologic response to B. burgdorferi infection is not detected. This may indicate lack of infection, lack of seroconversion or low/ undetectable antibody levels to B. burgdorferi. If clinically inidicated, a new serum sample should be submitted in 7-14 days. Positive IgG/Negative IgM: Indicative of B. burgdorferi infection at some time in the past. Positive IgG/Positive IgM: Indicative of active or previous B. burgdorferi infection. IgM Western blot is of diagnostic utility only during the first four weeks after the onset of disease. Negative IgG/Positive IgM: Indicative of early B. burgdorferi infection. A new serum specimen should be analyzed in days to demonstrate seroconversion of IgG. IgM Western blot is of diagnostic utility only during the first four weeks after the onset of disease. Specimens collected more than 1 month following the onset of disease with positive IgM and Negative IgG results more likely represent a false-positive. Price: Please contact Laboratory Customer Service for pricing information or Effective Date: January 7, 2013 References: B. burgdorferi (IgM) Marblot Strip Test System product insert, M/MB-29 Rev.5 B. burgdorferi (IgG) Marblot Strip Test System product insert, G/GB-29 Rev.5 Sample paper report included. Date: : January, 2013

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